U.S. patent application number 14/916328 was filed with the patent office on 2016-12-08 for downhole pressure maintenance system using reference pressure.
This patent application is currently assigned to HALLIBURTON ENERGY SERVICE, INC.. The applicant listed for this patent is HALLIBURTON ENERGY SERVICE, INC.. Invention is credited to Tyson Harvey Eiman, Thomas Jules Frosell, Gregory William Garrison, Syed Hamid, William Mark Richards, Colby Munro Ross.
Application Number | 20160356133 14/916328 |
Document ID | / |
Family ID | 56406164 |
Filed Date | 2016-12-08 |
United States Patent
Application |
20160356133 |
Kind Code |
A1 |
Hamid; Syed ; et
al. |
December 8, 2016 |
DOWNHOLE PRESSURE MAINTENANCE SYSTEM USING REFERENCE PRESSURE
Abstract
A method and apparatus that includes an elongated base pipe
having an external surface at least partially defining an external
region and an internal surface at least partially defining an
internal region; and a pressure maintenance device disposed in the
base pipe and includes a first flow path that extends between an
opening in the external surface and an opening in the internal
surface; a first valve that controls the flow of a first fluid
through the first flow path; a first pressure differential sensor
that controls the actuation of the first valve and is in fluid
communication with the external region; and a pressurized fluid
source in fluid communication with the first pressure differential
sensor; wherein a first pressure differential threshold associated
with the first pressure differential sensor is the difference
between a pressure within the external region and the pressurized
fluid source.
Inventors: |
Hamid; Syed; (Dallas,
TX) ; Eiman; Tyson Harvey; (Frisco, TX) ;
Garrison; Gregory William; (Dallas, TX) ; Ross; Colby
Munro; (Carrollton, TX) ; Richards; William Mark;
(Flower Mound, TX) ; Frosell; Thomas Jules;
(Irving, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HALLIBURTON ENERGY SERVICE, INC. |
Houston |
TX |
US |
|
|
Assignee: |
HALLIBURTON ENERGY SERVICE,
INC.
Houston
TX
|
Family ID: |
56406164 |
Appl. No.: |
14/916328 |
Filed: |
January 13, 2015 |
PCT Filed: |
January 13, 2015 |
PCT NO: |
PCT/US2015/011225 |
371 Date: |
March 3, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 34/10 20130101;
E21B 43/04 20130101; E21B 43/12 20130101; E21B 21/08 20130101; E21B
43/14 20130101; E21B 34/063 20130101; E21B 33/12 20130101; E21B
47/06 20130101; E21B 21/001 20130101; E21B 47/001 20200501; E21B
34/08 20130101 |
International
Class: |
E21B 43/12 20060101
E21B043/12; E21B 34/06 20060101 E21B034/06; E21B 43/14 20060101
E21B043/14; E21B 34/10 20060101 E21B034/10; E21B 21/08 20060101
E21B021/08; E21B 21/00 20060101 E21B021/00; E21B 47/00 20060101
E21B047/00; E21B 33/12 20060101 E21B033/12; E21B 47/06 20060101
E21B047/06; E21B 43/04 20060101 E21B043/04 |
Claims
1. A completion assembly comprising: an elongated base pipe having
an external surface at least partially defining an external region
and an internal surface at least partially defining an internal
region; and a pressure maintenance device disposed in the base pipe
and comprising: a first flow path that extends between an opening
in the external surface and an opening in the internal surface; a
first valve that controls the flow of a first fluid from the
internal region to the external region through the first flow path;
a first pressure differential sensor that controls the actuation of
the first valve and is in fluid communication with the external
region; and a pressurized fluid source in fluid communication with
the first pressure differential sensor; wherein a first pressure
differential threshold associated with the first pressure
differential sensor is the difference between a pressure within the
external region and the pressurized fluid source.
2. The completion assembly of claim 1, wherein the pressure
maintenance device further comprises: a second valve that controls
the flow of the first fluid from the internal region to the
external region through the first flow path; a second pressure
differential sensor that controls the actuation of the second
valve; wherein the second pressure differential sensor is in fluid
communication with the external region and the internal region; and
wherein a second pressure differential threshold associated with
the second pressure differential sensor is the difference between a
pressure within the internal region and the pressure within the
external region.
3. The completion assembly of claim 2, wherein the pressure
maintenance device further comprises: a second flow path that
extends between the pressurized fluid source and the external
region; a third valve that controls the flow of a second fluid
through the second flow path and towards the pressurized fluid
source; a third pressure differential sensor that controls the
actuation of the third valve; wherein the third pressure
differential sensor is in fluid communication with the external
region and the first flow path; and wherein a third pressure
differential threshold associated with the third pressure
differential sensor is the difference between a pressure within the
first flow path and the pressure within the external region.
4. The completion assembly of claim 3, wherein the pressurized
fluid source is an accumulator.
5. The completion assembly of claim 4, wherein the pressure
maintenance device further comprises at least one of: a pressure
relief valve that is in fluid communication with the pressurized
fluid source and with the external region; and a rupture disk that
is in fluid communication with the pressurized fluid source and
with the external region.
6. The completion assembly of claim 3, wherein the pressure
maintenance device further comprises: a fourth valve that controls
the flow of the fluid through the first flow path, the fourth valve
being a flow control valve; and a fourth pressure differential
sensor that controls the actuation of the fourth valve.
7. The completion assembly of claim 6, wherein the fourth valve is
located along the first flow path between the opening in the
external surface and the first valve; wherein the first valve is
located along the first flow path between the fourth valve and the
second valve; and wherein the second valve is located along the
first flow path between the first valve and the opening in the
internal surface.
8. A method of maintaining an isolated portion of an external
region of a completion string within a predetermined pressure
range, the method comprising: positioning a completion string that
has an internal surface that at least partially defines an internal
region and an external surface that at least partially defines an
external region within a wellbore; pressurizing a pressurized fluid
source located within a pressure maintenance device that is located
within a wall of the completion string to a reference pressure that
is associated with a wellbore hydrostatic pressure within the
external region; isolating a portion of the external region from
the wellbore hydrostatic pressure to form the isolated portion of
the external region; and allowing a first fluid within the internal
region to flow through a first flow path within the pressure
maintenance device to the isolated portion of the external region
when a pressure differential between the external region and the
reference pressure is less than a first pressure differential
threshold that is associated with the predetermined pressure
range.
9. The method of claim 8, further comprising preventing the first
fluid within the internal region from flowing through the first
flow path when a pressure differential between the internal region
and the external region exceeds a second pressure differential
threshold.
10. The method of claim 8, wherein the pressurized fluid source
comprises an accumulator in fluid communication with the external
region; and wherein pressurizing the pressurized fluid source to
the reference pressure that is associated with the wellbore
hydrostatic pressure within the external region comprises: allowing
a second fluid to pressurize the accumulator to the reference
pressure when the pressure differential between a pressure within
the first flow path and the external region is less than a fourth
pressure differential threshold; and preventing the second fluid
from pressurizing the accumulator after the pressure differential
between the internal region and the external region exceeds the
fourth pressure differential threshold.
11. The method of claim 8, wherein the pressure maintenance device
comprises a relief valve that is in fluid communication with the
pressurized fluid source and with the external region; and wherein
the method further comprises depressurizing the pressurized fluid
source when a first relief pressure differential threshold
associated with the relief valve is exceeded.
12. The method of claim 8, wherein the pressure maintenance device
comprises a rupture disk that is in fluid communication with the
pressurized fluid source and with the external region; and wherein
the method further comprises depressurizing the pressurized fluid
source when a second relief pressure differential threshold
associated with the rupture disk is met or exceeded.
13. The method of claim 8, wherein allowing the first fluid within
the internal region to flow through the first flow path when a
pressure differential between the external region and the reference
pressure is less than a first pressure differential threshold that
is associated with the predetermined pressure range comprises
opening a first valve that controls the flow of the first fluid
through the first flow path.
14. The method of claim 9, wherein preventing the first fluid
within the internal region from flowing through the first flow path
when a pressure differential between the internal region and the
external region exceeds a second pressure differential threshold
comprises closing a second valve that controls the flow of the
first fluid through the first flow path.
15. The method of claim 14, further comprising allowing the first
fluid to flow through the first flow path when a third pressure
differential across a third valve exceeds a third pressure
differential threshold associated with the third valve.
16. The method of claim 9, wherein isolating a portion of the
external region to form the isolated portion of the external region
comprises setting a packer that is disposed on the completion
string.
17. A method of providing pressure maintenance comprising:
positioning a completion string within a wellbore, the completion
string having an internal surface that at least partially defines
an internal region and an external surface that at least partially
defines an external region; isolating a portion of the external
region from a wellbore hydrostatic pressure; fluidically connecting
the internal region to the isolated portion of the external region
via a first flow path; providing a first valve that controls the
flow of a first fluid through the first flow path, the first valve
comprising a first pressure differential sensor; opening the first
valve when the first pressure differential sensor measures a
pressure differential between an external pressure within the
isolated portion of the external region and a reference pressure
that is less than a first pressure threshold; and closing the first
valve when the pressure differential between the external pressure
and the reference pressure is greater than or equal to the first
pressure threshold.
18. The method of claim 17, further comprising: providing a second
valve that controls the flow of the first fluid through the first
flow path, the second valve comprising a second pressure
differential sensor; opening the second valve when the second
pressure differential sensor measures a pressure differential
between an internal pressure associated with the internal region
and the external pressure that is less than a second pressure
threshold; and closing the second valve when the pressure
differential between the internal pressure and the external
pressure within the isolated portion of the external region is
greater than or equal to the second pressure threshold.
19. The method of claim 18, further comprising providing a flow
control valve that controls the flow of the first fluid through the
first flow path.
20. The method of claim 18, further comprising: pressurizing an
accumulator that is located within the completion string and that
is in fluid communication with the external region to the external
pressure, wherein pressurizing the accumulator comprises flowing a
second fluid from the external region in a direction towards the
accumulator; and closing a fifth valve that controls the flow of
the second fluid when a fifth pressure differential sensor measures
a pressure differential between the first flow path and the
external pressure that is greater than a fifth pressure threshold
associated with the fifth pressure differential sensor.
21. The method of claim 17, wherein the first pressure differential
sensor comprises a spring.
22. The method of claim 17, wherein the reference pressure is the
wellbore hydrostatic pressure.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to a downhole
pressure maintenance system, and specifically a pressure
maintenance system that maintains a pressure within an isolated
annulus of a wellbore within a predetermined pressure range.
BACKGROUND
[0002] After a well is drilled and a target reservoir has been
encountered, completion and production operations are performed,
which may include gravel packing operations. Generally, gravel
packing operations include placing a lower completion assembly,
which forms part of a working string, downhole within a target
reservoir in a formation. In a multi-zone completion, a number of
packers are located within the lower completion assembly and are
activated to isolate a portion of a wellbore annulus formed between
the working string and the casing (if a cased hole) or the
formation (if an open hole). Each of these portions may be
production zones that are subsequently packed with gravel or coarse
sand. Often, after one of the packers is set but prior to the
gravel packing of the production zones, each production zone is
isolated from the wellbore hydrostatic pressure. As the formation
absorbs drilling fluids from each production zone, the wellbore
annulus pressure within each of the production zones may drop,
which may cause collapse of an open hole or influx of sand in an
unconsolidated cased hole installation.
[0003] The present disclosure is directed to a downhole pressure
maintenance system that overcomes one or more of the shortcomings
in the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Various embodiments of the present disclosure will be
understood more fully from the detailed description given below and
from the accompanying drawings of various embodiments of the
disclosure. In the drawings, like reference numbers may indicate
identical or functionally similar elements.
[0005] FIG. 1 is a schematic illustration of an oil and gas rig
operably coupled to a lower completion system, the lower completion
system including a pressure maintenance device, according to an
exemplary embodiment of the present disclosure;
[0006] FIG. 2 is a schematic illustration of the lower completion
system of FIG. 1, according to an exemplary embodiment of the
present disclosure;
[0007] FIG. 2A is an enlarged view of a portion of the lower
completion system of FIG. 2, according to an exemplary embodiment
of the present disclosure;
[0008] FIG. 3 is a hydraulic diagram of a first embodiment of the
pressure maintenance device of FIG. 1, according to an exemplary
embodiment of the present disclosure;
[0009] FIG. 4 is a hydraulic diagram of a second embodiment of the
pressure maintenance device of FIG. 1, according to an exemplary
embodiment of the present disclosure;
[0010] FIG. 5 is a flow chart illustration of a method of operation
of the pressure maintenance devices of FIGS. 3 and 4, according to
an exemplary embodiment of the present disclosure;
[0011] FIG. 6 is a flow chart diagram of a step of the method of
FIG. 5, according to an exemplary embodiment of the present
disclosure;
[0012] FIG. 7 is a flow chart diagram of another step of the method
of FIG. 5, according to an exemplary embodiment of the present
disclosure;
[0013] FIG. 8 is a section view of a third embodiment of the
pressure maintenance device of FIG. 1, according to an exemplary
embodiment of the present disclosure, the pressure maintenance
device including a controller;
[0014] FIG. 8A is a schematic illustration of the controller,
according to an exemplary embodiment of the present disclosure;
[0015] FIG. 9 is a flow chart diagram of a method of operation of
the pressure maintenance device of FIG. 8, according to an
exemplary embodiment of the present disclosure;
[0016] FIG. 10 is a hydraulic diagram of a fourth embodiment of the
pressure maintenance device of FIG. 1, according to an exemplary
embodiment of the present disclosure;
[0017] FIG. 11 is a section view of the fourth embodiment of the
pressure maintenance device of FIG. 1, according to an exemplary
embodiment of the present disclosure;
[0018] FIG. 12 is a section view of a of a portion of a fifth
embodiment of the pressure maintenance device of FIG. 1, according
to an exemplary embodiment of the present disclosure;
[0019] FIG. 13 is a section view of a portion of a sixth embodiment
of the pressure maintenance device of FIG. 1, according to an
exemplary embodiment of the present disclosure;
[0020] FIG. 14 is a section view of a seventh embodiment of the
pressure maintenance device of FIG. 1, according to an exemplary
embodiment of the present disclosure;
[0021] FIG. 15 is another section view of the seventh embodiment of
the pressure maintenance device of FIG. 1, according to an
exemplary embodiment of the present disclosure;
[0022] FIG. 16 is yet another section view of the seventh
embodiment of the pressure maintenance device of FIG. 1, according
to an exemplary embodiment of the present disclosure; and
[0023] FIG. 17 is a block diagram of a computer system adapted for
implementing a pressure maintenance device, according to an
exemplary embodiment of the present disclosure.
DETAILED DESCRIPTION
[0024] Illustrative embodiments and related methods of the present
disclosure are described below as they might be employed in a
downhole pressure maintenance system. In the interest of clarity,
not all features of an actual implementation or method are
described in this specification. It will of course be appreciated
that in the development of any such actual embodiment, numerous
implementation-specific decisions must be made to achieve the
developers' specific goals, such as compliance with system-related
and business-related constraints, which will vary from one
implementation to another. Moreover, it will be appreciated that
such a development effort might be complex and time-consuming, but
would iii nevertheless be a routine undertaking for those of
ordinary skill in the art having the benefit of this disclosure.
Further aspects and advantages of the various embodiments and
related methods of the disclosure will become apparent from
consideration of the following description and drawings.
[0025] The foregoing disclosure may repeat reference numerals
and/or letters in the various examples. This repetition is for the
purpose of simplicity and clarity and does not in itself dictate a
relationship between the various embodiments and/or configurations
discussed. Further, spatially relative terms, such as "beneath,"
"below," "lower," "above," "upper," "uphole," "downhole,"
"upstream," "downstream," and the like, may be used herein for ease
of description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. The
spatially relative terms are intended to encompass different
orientations of the apparatus in use or operation in addition to
the orientation depicted in the figures. For example, if the
apparatus in the figures is turned over, elements described as
being "below" or "beneath" other elements or features would then be
oriented "above" the other elements or features. Thus, the
exemplary term "below" may encompass both an orientation of above
and below. The apparatus may be otherwise oriented (rotated 90
degrees or at other orientations) and the spatially relative
descriptors used herein may likewise be interpreted
accordingly.
[0026] Referring initially to FIG. 1, an offshore oil or gas
platform is schematically illustrated and generally designated 10.
A semi-submersible platform 15 is positioned over a submerged oil
and gas formation 20 located below a sea floor 25. A subsea conduit
30 extends from a deck 35 of the platform 15 to a subsea wellhead
installation 40, including blowout preventers 45. The platform 15
has a hoisting apparatus 50, a derrick 55, a travel block 60, a
hook 65, and a swivel 70 for raising and lowering pipe strings,
such as a substantially tubular, axially extending working string
75.
[0027] A wellbore 80 extends through the various earth strata
including the formation 20 and has a casing string 85 cemented
therein. Disposed in a substantially horizontal portion of the
wellbore 80 is a lower completion assembly 87 that forms a part of
the working string 75 and that may include an isolation packer 90
and a sump packer 95. The lower completion assembly 87 may also
include packers 100 and 105 that at least partially define a first
zone 110, a second zone 115, and a third zone 120 of the lower
completion assembly 87. In one or more exemplary embodiments, a
portion of the formation 20 that surrounds the first zone 110, the
second zone 115, and the third zone 120 may be associated with a
reservoir pressure. In one or more exemplary embodiments, the first
zone 110, the second zone 115, and the third zone 120 are
associated with production zones. In one or more exemplary
embodiments, each of a flow regulating systems 125, 130, and 135 is
located on the lower completion assembly 87 within each of the
third zone 120, the second zone 115, and the first zone 110,
respectively. In one or more exemplary embodiments, a pressure
maintenance device ("PMD") 140 is located on or in the lower
completion assembly 87 within each of the first zone 110, the
second zone 115, and the third zone 120. One or more communication
cables, such as an electric cable 145, may pass through the packers
90, 100, and 105 and may be provided and extend from the lower
completion assembly 87 to the surface in an wellbore annulus 150
formed between the working string 75 and the casing 85 or an
interior surface 80a of the wellbore 80 when the wellbore 80 is an
open hole wellbore.
[0028] Even though FIG. 1 depicts a horizontal wellbore, it should
be understood by those skilled in the art that the apparatus
according to the present disclosure is equally well suited for use
in wellbores having other orientations including vertical
wellbores, slanted wellbores, multilateral wellbores or the like.
Also, even though FIG. 1 depicts an offshore operation, it should
be understood by those skilled in the art that the apparatus
according to the present disclosure is equally well suited for use
in onshore operations. Further, even though FIG. 1 depicts an open
hole completion, it should be understood by those skilled in the
art that the apparatus according to the present disclosure is
equally well suited for use in cased hole completion.
[0029] In one or more exemplary embodiments and illustrated in FIG.
2, the PMD 140 has an exterior surface 140a and an interior surface
140b. In an exemplary embodiment, the interior surface 140b at
least partially defines an internal region or a completion string
annulus 165. In one or more exemplary embodiments, the exterior
surface 140a at least partially defines an external region or the
wellbore annulus 150. The PMD 140 may be located within the lower
completion assembly 87 to fluidically connect the wellbore annulus
150 and the completion string annulus 165 that is formed between
the inner surface of the lower completion assembly 87 and an
exterior surface of a tubing string 166 that extends within the
lower completion assembly 87.
[0030] In one or more exemplary embodiments and illustrated in
FIGS. 2A and 3, a first embodiment of the PMD 140 is a Dual Port
PMD ("DPPMD") 173 that has an exterior surface 173a and an interior
surface 173b. The DPPMD 173 may be located within the lower
completion assembly 87 to fluidically connect the wellbore annulus
150 with the completion string annulus 165. In one or more
exemplary embodiments, and as shown in FIG. 3, the DPPMD 173 may
include a flow path 175 that extends from an opening 180 through
the exterior surface 173a to an opening 185 through the interior
surface 173b of the DPPMD 173 to fluidically connect the completion
string annulus 165 and the wellbore annulus 150. The DPPMD 173 may
include valves 190, 195, and 200 that are located along the flow
path 175 and between the opening 185 and a check valve 205. In one
or more exemplary embodiments, the valves 190, 195, and 200 control
the flow of a fluid from the completion string annulus 165 to the
wellbore annulus 150. In an exemplary embodiment, the valves 190
and 195 may be two-position spool valves that open or close based
on a pressure differential. In one or more exemplary embodiments,
the check valve 205 is located along the flow path 175 such that
the fluid is prevented from flowing through the opening 180 and
entering the valve 200. In one or more exemplary embodiments, the
DPPMD 173 also includes a restrictor 300 located along the flow
path 175 and between the check valve 205 and the valve 200. In one
or more exemplary embodiments, the opening 185 of the DPPMD 173 is
fluidically connected to the completion string annulus 165 within
the first zone 110. In one or more exemplary embodiments, the valve
190 is located along the flow path 175 between the opening 185 and
the valve 195. In one or more exemplary embodiments, the valve 195
is located along the flow path 175 between the valves 190 and 200.
In one or more exemplary embodiments the valve 200 is located along
the flow path 175 between the valve 195 and the opening 180.
[0031] In an exemplary embodiment, the flow path 175 forms a first
section 175a that extends from the opening 185 to the valve 190, a
second section 175b that extends from the valve 190 to the valve
195, a third section 175c that extends from the valve 195 to the
valve 200, a fourth section 175d that extends from the valve 200 to
the restrictor 300, and a fifth section 175e that extends from the
check valve 205 to the opening 180.
[0032] In one or more exemplary embodiments, the valve 190 closes
when a first pressure differential exceeds a first threshold
pressure, such as for example 2,500 psi. In one or more exemplary
embodiments, the first pressure differential is a pressure
differential between an internal pressure, which is a pressure
within the internal region, or the completion string annulus 165,
and an external pressure, which is a pressure associated with the
external region, or the wellbore annulus 150. Otherwise, and when
the first pressure differential is less than 2,500 psi, the valve
190 is open to allow the fluid to flow through the flow path 175
from the first section 175a to the second section 175b. That is,
when the internal pressure exceeds the external pressure by the
first pressure differential, the valve 190 is closed. However, when
the internal pressure exceeds the external pressure by an amount
less than the first pressure differential, when the external
pressure is equal to the internal pressure, and when the external
pressure exceeds the internal pressure, the valve 190 remains open.
In one or more exemplary embodiments, the first threshold pressure
may be any predetermined pressure, such as for example 1,000 psi,
1,500 psi, 2,000 psi, 3,000 psi, 3,500 psi, or 4,000 psi.
[0033] In one or more exemplary embodiments, the valve 195 closes
when a second pressure differential exceeds a second threshold
pressure. Otherwise, the valve 195 remains open. In one or more
exemplary embodiments, the second pressure differential is a
pressure differential between the external pressure and a reference
pressure. In one or more exemplary embodiments, the second
threshold pressure may be any predetermined pressure, such as for
example 100 psi, 200 psi, 300 psi, 400 psi, or 500 psi. In one or
more exemplary embodiments, the second threshold pressure
correlates to the desired pressure differential between the
reservoir pressure and the pressure in the wellbore annulus 150. In
an exemplary embodiment, the second threshold is 200 psi. In an
exemplary embodiment, and when the reservoir pressure is 10,000 psi
and the second threshold pressure is 200 psi, the ideal pressure
within the wellbore annulus 150 is between 10,000 psi and 10,200
psi.
[0034] In one or more exemplary embodiments, the valve 200 is a
flow control valve that opens when a third pressure differential
exceeds a third threshold pressure. In an exemplary embodiment, the
third threshold pressure is a pressure differential between the
pressure within the third section 175c of the flow path 175 and the
fourth section 175d of the flow path 175. In one or more exemplary
embodiments, the third pressure differential may be any
predetermined pressure, such as for example 50 psi. In an exemplary
embodiment, the third pressure differential may be 150 psi. In one
or more exemplary embodiments, the valve 200 controls the flow of
the fluid through the flow path 175. For example, when the pressure
within the third section 175c of the flow path 175 exceeds the
pressure within the fourth section 175d of the flow path 175 by 150
psi, the valve 200 opens. In an exemplary embodiment and when the
valve 200 is open, the fluid flows through the restrictor 300,
which creates a back pressure that is communicated through a pilot
line 305 as a feedback signal to flow control valve 200. In an
example embodiment, this causes the valve 200 to move to create a
higher pressure across the valve 200 thereby reducing the flow
rate. In an exemplary embodiment, this continues until a stable
value of flow rate is achieved, which will cause a spool in the
valve 200 to remain in a stable state.
[0035] In one or more exemplary embodiments, the DPPMD 173 may also
include a reference pressure assembly 310, which may include a
valve 315 that controls the flow of a fluid into a pressurized
fluid source, or an accumulator 320, from a pilot line 326 that
extends between the accumulator 320 and the external region. In an
exemplary embodiment, the valve 315 is also fluidically connected
to the external region via the pilot line 326 and the second
section 175b of the flow path 175 via a pilot line 327. In an
exemplary embodiment, the fluid that pressurizes the accumulator
320 flows through the pilot line 326 towards the accumulator 320.
In an exemplary embodiment, a fluid located within the wellbore
annulus 150 pressurizes the fluid that flows through the pilot line
326 to pressurize the accumulator 320. In one or more exemplary
embodiments, the accumulator 320 is pressurized to an initial
pressure at the surface, such as for example using a fluid such as
a nitrogen gas. A check valve 330 may form a portion of the pilot
line 326 to prevent the flow of a fluid from the accumulator 320
and towards the valve 315. However, the check valve 330 may be
omitted from the DPPMD 173. In one or more exemplary embodiments, a
filtering device 331 and/or a piston 332 may form a portion of the
pilot line 327. In an exemplary embodiments, a pilot line 335
extends between the accumulator 320 and the valve 195. In one or
more exemplary embodiments, a pressure relief valve 340 is
fluidically connected to the pilot line 335 and is configured to
depressurize the reference pressure assembly 310 when the DPPMD 173
is pulled up to the surface. In an exemplary embodiment, the valve
315 may be a two-position spool valve having a latch feature that
secures the valve 315 in the closed position. In an exemplary
embodiment, the valve 315 closes when a fourth pressure
differential exceeds a fourth threshold pressure, such as for
example 100 psi. However, a variety of fourth threshold pressures
are contemplated here. In an exemplary embodiment, the fourth
threshold pressure is a pressure differential between the pressure
within the second section 175b of the flow path 175 and the
external pressure. In one or more exemplary embodiments, the fourth
threshold pressure is less than the first threshold pressure so
that the valve 315 will close prior to the valve 190 closing. In
one or more exemplary embodiments, the accumulator 320 is a piston
type accumulator such as for example, a gas-charged accumulator
that is a hydraulic accumulator with gas as the compressible
medium. In an exemplary embodiment, the pressure relief valve 340
is also connected to the external region via a pilot line 341. In
an exemplary embodiment, the pressure relief valve 340 may be rated
at 5,000 psi change of pressure, although a variety of pressure
ratings are contemplated here. In an exemplary embodiment, the
reference pressure assembly 310 may also include a rupture disk 342
that is fluidically connected to the pilot line 335 and the
external region via a pilot line 343. In an exemplary embodiment,
the rupture disk 342 may be rated at 7,000 psi, although a variety
of pressure ratings are contemplated here.
[0036] In one or more exemplary embodiments, the DPPMD 173 may also
include a pilot line 345 that extends between the external region
and the valve 195. In one or more exemplary embodiments, the DPPMD
173 may also include a pilot line 346 that extends between the
external region and the valve 190. In an exemplary embodiment, the
DPPMD 173 may also include a pilot line 347 that extends from the
pilot line 345 to the valve 200. A filtering device 360 and/or a
piston 365 may form a portion of the pilot line 345. In an
exemplary embodiment, a screen 375 and/or a piston 380 may form a
portion of the pilot line 305. In one or more exemplary
embodiments, the DPPMD 173 also includes a pilot line 381 extending
between the internal region or the completion string annulus 165
(via the first portion 175a of the flow path 175) and the valve
190. A filtering device 382 and/or a piston 383 may form a portion
of the pilot line 381.
[0037] In an exemplary embodiment, the DPPMD 173 also includes a
flow path 384 that extends from an opening 385 that is exposed to a
pressure within completion string annulus 165 to the second section
175b of the flow path 175. In an exemplary embodiment, a valve 386
may be located along the flow path 384. In one or more exemplary
embodiments, a pilot line 387 extends between the accumulator 320
and the valve 386. In one or more exemplary embodiments, the valve
386 is fluidically connected to the pilot line 381. In an exemplary
embodiment, the valve 386 may be a two-position spool valve that
closes when a fifth pressure differential exceeds a fifth threshold
pressure. In one or more exemplary embodiments, the fifth pressure
differential is a difference between the pressure in the
accumulator 320 and the internal pressure. That is, the fifth
pressure differential is based on the reference pressure and the
internal pressure. Generally, the valve 386 closes when the
reference pressure exceeds the internal pressure by the fifth
threshold pressure. In one or more exemplary embodiments, a
filtering device 388 is located along the flow path 384 between the
opening 385 and the valve 386. In an exemplary embodiment, the
opening 185 and the opening 385 are spaced longitudinally along the
lower completion assembly 87 such that the opening 185 is
fluidically connected to the completion string annulus 165 at a
location uphole from the sump packer 95 and the opening 385 is
fluidically connected to the completion string annulus 165 at a
location downhole from the sump packer 95. In one or more exemplary
embodiments, the opening 385 is fluidically connected to the
completion string annulus 165 at a location outside of the
production zone. Thus, pressurized fluid within the completion
string annulus 165 that is located downhole from the sump packer 95
may be used to pressurize the wellbore annulus 150 of the first
zone 110, the second zone 115, and the third zone 120. Often, when
the packers 100 and 105 are being set, the pressure within the
completion string annulus 165 that is located uphole from the sump
packer 95 may increase greatly, thus exceeding the first threshold
pressure to close the valve 190. In order to continue pressurizing
the external region, or the wellbore annulus 150 associated with
the production zone of the lower completion system 87, while the
isolation packers 100 and 105 are being set, pressurized fluid
within the completion string annulus 165 that is located downhole
from the sump packer 95 may flow through the flow path 384. In one
or more exemplary embodiments, the DPPMD 173 may also include a
filtering device 389 that may form a portion of the first section
175a of the flow path 175. In one or more exemplary embodiments, a
filtering device 390 may form a portion of the fifth section 175e
of the flow path 175. In one or more exemplary embodiments, the
filtering devices 331, 360, 375, 382, 388, 389, and 390 may be any
type of device to screens large solid particles, such as for
example, a screen. In an exemplary embodiment, a check valve 391
may be located along the flow path 384 to prevent the fluid from
flowing from the second section 175b of the flow path 175 to the
valve 386.
[0038] In one or more exemplary embodiments and illustrated in FIG.
4, a second embodiment of the PMD 140 is a Single Port PMD
("SPPMD") 392. In one or more exemplary embodiments, the SPPMD 392
has an exterior surface and an interior surface. In one or more
embodiments, the SPPMD 392 is substantially similar to the DPPMD
173 except that the SPPMD 392 omits the flow path 384, the opening
385, the filtering device 388, the valve 386, the check valve 391,
and the pilot line 387 and instead, may include a valve 393 located
along the fluid line 175 and between the screen 389 and the valve
190. In an exemplary embodiment, the valve 393 is a two-position
spool valve that is in an initially in a closed position. In an
exemplary embodiment, the valve 393 may be in fluid communication
with the internal pressure via a pilot line 394 and may be in fluid
communication with the external pressure via a pilot line 395. In
an exemplary embodiment, the valve 393 is held in the closed
position using a shear pin. In an exemplary embodiment, the shear
pin will shear when the valve 393 is exposed to a predetermined
pressure differential, such as 500 psi. In an exemplary embodiment,
the valve 393 includes a collet and corresponding groove that
secures the valve 393 in the open position. In an exemplary
embodiment, the opening 180 of the SPPMD 392 is formed through an
exterior surface of the SPPMD 392 instead of the exterior surface
173a of the DPPMD 173 and the opening 185 is formed through the
interior surface of the SPPMD 392 instead of the interior surface
173b of the DPPMD 173. In one or more exemplary embodiments, the
opening 185 of the SPPMD 392 is fluidically connected to the
internal region, or the completion string annulus 165, of the
second zone 115.
[0039] In one or more exemplary embodiments, the PMD 140 in the
third zone 120 is a SPPMD 392', which is substantially identical or
identical to the SPPMD 392, and therefore the SPPMD 392' will not
be described in further detail. Reference numerals used to refer to
the features of the SPPMD 392 that are substantially identical to
the features of the SPPMD 392' will correspond to the reference
numerals used to refer to the features of the SPPMD 392. In one or
more exemplary embodiments, the opening 185 of the SPPMD 392' is
fluidically connected to the internal region, or the completion
string annulus 165, of the third zone 120.
[0040] With reference to FIG. 5 and with continuing reference to
FIGS. 1-4, in one or more embodiments, a method of operating the
DPPMD 173, the SPPMD 392, and the SPPMD 392' is generally referred
to by the reference numeral 400 and may include positioning the
lower completion system 87 downhole to pressurize the reference
pressure assembly 310 associated with each of the SPPMD 392, the
SPPMD 392' and the DPPMD 173 at step 405; setting the packer 90 to
isolate a production zone of the lower completion system 87 and to
fix the reference pressure within the assemblies 310 of the SPPMD
392, the SPPMD 392', and the DPPMD 173 at step 410; maintaining a
predetermined pressure range in the production zone of the lower
completion system 87 using the DPPMD 173 at step 415; setting the
isolation packers 100 and 105 to form the first zone 110, the
second zone 115, and the third zone 120 at step 420; maintaining a
predetermined pressure range in the first zone 110 using the DPPMD
173 at step 425; gravel packing the first zone 110 while
maintaining the predetermined pressure range in the third zone 120
using the SPPMD 392' and in the second zone 115 using the SPPMD 392
at step 430; and gravel packing the second zone 115 while
maintaining the predetermined pressure range in the third zone 120
using the SPPMD 392' at step 435.
[0041] At the step 405, the lower completion system 87 is
positioned downhole to pressurize the assemblies 310 of the SPPMD
392', the SPPMD 392, and the DPPMD 173. Referring to FIG. 4, when
the lower completion system 87 and the SPPMD 392 are lowered
downhole, the valve 200 will open when the third pressure
differential is exceeded. As the lower completion system 87 is
positioned downhole, the first pressure differential does not
exceed the first threshold pressure associated with the valve 190
and the valve 190 remains open. Additionally, the second pressure
differential does not exceed the second threshold pressure
associated with the valve 195 and the valve 195 remains open.
Additionally, the fourth pressure differential does not exceed the
fourth threshold pressure and the valve 315 remains open to allow
for the accumulator 320 to be pressurized to the external pressure
if the external pressure is greater than the initial pressure of
the accumulator 320. In an exemplary embodiment, the fluid may be
entering the accumulator 320 to pressurize the accumulator 320 when
a depth of 20,000 ft. is achieved, however, this is dependent upon
the initial pressure of the accumulator 320. In one or more
exemplary embodiments, the lower completion system 87 may be an
Enhanced Single-Trip Multizone ("ESTMZ.TM.") System. As the lower
completion system 87 extends downhole, the internal pressure and
the external pressure increase and the fluid within the flow path
326 compresses a nitrogen-filled bladder to create the reference
pressure within the accumulator 320 of the SPPMD 392. The reference
pressure assemblies 310s of the DPPMD 173 and of the SPPMD 392' are
pressurized in a substantially similar manner to pressurizing the
reference pressure assembly 310 of the SPPMD 392 and therefore
additional detail will not be provided here. In one or more
exemplary embodiments, the reference pressure assembly 310 for each
of the SPPMD 392, SPPMD 392' and DPPMD 173 may be pressurized to a
different reference pressure, depending on the location of each of
the SPPMD 392, SPPMD 392' and DPPMD 173 in the wellbore, along with
a variety of other factors.
[0042] At the step 410, the packer 90 is set to isolate the
production zone of the lower completion system 87 and to fix the
reference pressures within each of the SPPMD 392', the SPPMD 392,
and the DPPMD 173. In one or more exemplary embodiments, setting
the packer 90 will isolate the production zone of the lower
completion system 87 from the wellbore hydrostatic pressure. In one
or more exemplary embodiments, setting the packer 90 includes
increasing the internal pressure within the completion string
annulus 165 so that the packer 90 may expand to fluidically isolate
the wellbore annulus 150 of the production zone of the lower
completion system 87 from the wellbore annulus 150 that is uphole
from the packer 90. In one or more exemplary embodiments, the
internal pressure may be increased to about 3,600 psi, however any
internal pressure is contemplated here. In one or more exemplary
embodiments, increasing the internal pressure can cause the fourth
pressure differential to exceed the fourth threshold pressure to
close the valve 315. In one or more exemplary embodiments, the
valve 315 has a latching mechanism to prevent the valve 315 from
reopening once the fourth pressure differential recedes below the
fourth threshold pressure. Accordingly, the accumulator 320 and the
pilot line 335 and a portion of the pilot line 326 can no longer be
pressurized and the reference pressure is "set" or fixed at the
pressure within the accumulator 320 when the valve 315 closes. In
one or more exemplary embodiments, increasing the internal pressure
can also cause the first pressure differential to exceed the first
threshold pressure differential to close the valve 190.
[0043] At the step 415 and referring back to FIG. 3, the
predetermined pressure range is maintained in the wellbore annulus
150 of the production zone of the lower completion system 87 using
the DPPMD 173. In one or more exemplary embodiments, the
predetermined pressure range is a pressure range equal to or
greater than the highest reservoir pressure. Generally, and when
the completion string annulus 165 is isolated from the wellbore
annulus 150, isolating the production zone of the lower completion
system 87 from the wellbore hydrostatic pressure will result in the
reduction of the external pressure or depletion of a hydrostatic
overbalance pressure, as the fluid within the wellbore annulus 150
seeps or leaks into the surrounding formation 20. If the external
pressure continues to recede, then the wellbore 80 may collapse if
it is an open hole wellbore. Alternatively, the filter cake may
collapse. If the wellbore 80 is a cased hole, formation sands from
one portion of the production zone may enter the annulus and exit
the production zone in another portion of the production zone to
mix formation sands. In one or more exemplary embodiments, and due
to the increased internal pressure within the completion string
annulus 165 on the uphole side of the sump packer 95 (i.e., the
first zone 110), the valve 190 of the DPPMD 173 may be closed. Due
to the opening 385 and flow path 384 fluidically connecting the
DPPMD 173 to the completion string annulus 165 at a location that
is on the downhole side of the sump packer 95, fluid from the
downhole side of the sump packer may be used to pressurize the
wellbore annulus 150 when the fifth pressure differential is not
exceeded. Assuming that the reference pressure is less than the
internal pressure during the step 415, the valve 386 will be open.
That is, the flow path 384, the opening 385, and the valve 386
allow for the DPPMD 173 to pressurize the wellbore annulus 150 even
while the internal pressure of the completion string annulus 165
associated with the first zone 110, the second zone 115, and the
third zone 120 exceed the first threshold pressure.
[0044] In one or more exemplary embodiments and as illustrated in
FIG. 6, the step 415 includes one or more of sub-steps of
determining whether the first pressure differential exceeds the
first threshold pressure at step 415a, if so, closing the valve 190
at step 415b and returning to the step 415a and if not, opening or
keeping the valve 190 open at step 415c, and simultaneously,
determining whether the fifth pressure differential exceeds the
fifth threshold pressure at step 415d, if so, closing the valve 386
at step 415e and returning to the step 415d, and if not, opening or
keeping open the valve 386 at step 415f, then after the steps 415a,
415b, 415c, 415d, 415e, and 415f, determining whether the second
pressure differential exceeds the second threshold pressure at step
415g, if yes, closing the valve 195 at step 415h and returning to
the step 415g, if no, opening or keeping open the valve 195 at step
415i, determining whether the third pressure differential exceeds
the third threshold pressure at step 415j, if not, closing the
valve 200 at step 415k and returning to step 415j, and if so,
opening or keeping the valve 200 open at step 415l, and allowing
fluid to flow from the completion string annulus 165 to the
wellbore annulus 150.
[0045] Returning to FIG. 5 and at the step 420, the packers 100 and
105 are set to form the first zone 110, the second zone 115, and
the third zone 120 of the production zone of the lower completion
system 87. In one or more exemplary embodiments, the internal
pressure increases to up to about 5,000 psi when the packers 100
and 105 are set, which closes the valve 190 but not the valve 386
(as the opening 385 is not exposed to the 5,000 psi pressure).
[0046] At the step 425, the predetermined pressure range is
maintained within the first zone 110 using the SPPMD 173. In an
exemplary embodiment, the step 425 is identical to the step 415 and
therefore, no additional detail will be provided here. However, as
the production zone is now separated into the first zone 110, the
second zone 115, and the third zone 120, the SPPMD 173 can only
maintain the first zone 110 within the predetermined pressure
range.
[0047] At the step 430, the first zone 110 is gravel packed while
the predetermine pressure range is maintained in the second zone
115 using the SPPMD 392 and the predetermined pressure range is
maintained in the third zone 120 using the SPPMD 392'. In one or
more exemplary embodiments, maintaining the predetermined pressure
range in the third zone 120 using the SPPMD 392' and maintaining
the predetermined pressure range in the second zone 115 using the
SPPMD 392 is identical to maintaining the predetermined pressure
range in the production zone using the DPPMD 173 except the
sub-steps 415d, 415e, and 415f are omitted, as shown in FIG. 7.
That is, the step of maintaining the predetermined pressure range
in the third zone 120 using the SPPMD 392' and/or maintaining the
predetermined pressure range in the second zone 115 using the SPPMD
392 includes one or more of sub-steps of determining whether the
first pressure differential exceeds the first threshold pressure at
the step 415a, if so, closing the valve 190 at the step 415b and
returning to the step 415a and if not, opening or keeping the valve
190 open at the step 415c, determining whether the second pressure
differential exceeds the second threshold pressure at the step
415g, if yes, closing the valve 195 at the step 415h and returning
to the step 415g, if no, opening or keeping open the valve 195 at
the step 415i, determining whether the third pressure differential
exceeds the third threshold pressure at the step 415j, if no,
closing the valve 200 at the step 415k and returning to the step
415j, and if so, opening or keeping the valve 200 open at the step
415l, and allowing fluid to flow from the completion string annulus
165 to the wellbore annulus 150 at the step 415m. In an exemplary
embodiment, maintaining the predetermined pressure range in the
third zone 120 using the SPPMD 392' and/or maintaining the
predetermined pressure range in the second zone 115 using the SPPMD
392 may occur at any time when the valves 190, 195, and 200 open.
In one or more exemplary embodiments and during the step 430, a
tool opens a port within the working string 75 that forms part of
the first zone 110 to pump a slurry into the wellbore annulus 150
of the first zone 110. In one or more exemplary embodiments and
while the first zone 110 is being gravel packed, the SPPMD 392
maintains the second zone 115 within the predetermined pressure
range in the manner described in the step 430 and the SPPMD 392'
maintains the third zone 120 at the predetermined pressure range in
the manner described in the step 430. In an exemplary embodiment,
the fluid entering a screen associated with the first zone 110
flows through the completion string annulus 165 in the second zone
115 and the third zone 120 and the SPPMD 392 and/or the SPPMD 392'
may use this fluid to pressurize the wellbore annulus 150
associated with each of the second zone 115 and the third zone 120.
Once the first zone 110 is gravel packed or frac-packed and ready
for production, the risk of wellbore collapse is less and the DPPMD
173 is not required to maintain the first zone 110 within the
predetermined pressure range.
[0048] Referring back to FIG. 5 and at the step 435, the second
zone 115 is gravel packed or frac-packed while the predetermine
pressure range is maintained in the third zone 120 using the SPPMD
392'. The step of maintaining the predetermined pressure range in
the third zone 120 using the SPPMD 392' at the step 435 is
identical to maintaining the predetermined pressure range in the
second zone 115 using the SPPMD 392' at the step 430. Once the
second zone 115 is gravel packed or frac-packed and ready for
production, the risk of wellbore collapse is less and the SPPMD 392
is not required to maintain the second zone 115 at the
predetermined pressure range.
[0049] The process continues until each of the first zone 110, the
second zone 115, and the third zone 120 of the production zone is
gravel packed and/or frac-packed.
[0050] In an exemplary embodiment, a PMD 140 identical to the SPPMD
392 may be used in place of the DPPMD 173 and the steps 415 and 425
are omitted from the method 400. In an exemplary embodiment, the
method 400 may also include a method of testing the lower
completion system 87 at or near the surface. In an exemplary
embodiment, the lower completion system 87 is lowered downhole to a
first distance, for example, to 300 feet downhole. In an exemplary
embodiment, the fluid is then flowed through the completion string
annulus 165 and the pressure in the completion string annulus 165
and/or the wellbore annulus 150 is increased to a pressure less
than the pressure differential associated with the valve 393, such
as 500 psi. The pressure within the completion string annulus 165
and/or the wellbore annulus 150 is monitored while the valve 393
remains closed. Thus, the lower completion system 87 may be tested
for leaks or other issues. Once the testing of the lower completion
system 87 is complete, the interior pressure within the completion
string annulus 165 may be increased such that the pressure
differential associated with the valve 393 is exceed. In an
exemplary embodiment, and once the pressure differential associated
with the valve 393 is exceeded, the shear pin in the valve 393 is
sheared and the collet is secured in the groove to lock the valve
393 in an open position.
[0051] In an exemplary embodiment, the pressure relief valve 340
and the rupture disk 342 are safety features useful in the event
the lower completion system 87 is returned to the surface. In an
exemplary embodiment, and when the pressure within the pressure
assembly 310 has been "set" or fixed at 10,000 psi, a pressure
differential between the pressure assembly 310 and the exterior
region increases as the depth of the lower completion system 87 is
reduced. Once the pressure differential reaches the rating of the
pressure relief valve 340, such as 5,000 psi, the pressure relief
valve 340 opens to decrease the pressure within the pressure
assembly 310. In an exemplary embodiment and if the pressure relief
valve 340 fails, then when the pressure differential reaches the
rating of the rupture disc 342, such as 7,000 psi, the rupture disc
342 ruptures to decrease the pressure within the pressure assembly
310.
[0052] In one or more embodiments, each of the first, second,
third, fourth, and fifth threshold pressures is a function of
springs used within the valves 190, 195, 200, 315, and 386,
respectively. In one or more exemplary embodiments, each spring
constant and the initial pre-compression of the springs within the
valves 190, 195, 200, 315, and 386 is selected to achieve a
predetermined pressure differential threshold for each of the
valves 190, 195, 200, 315, and 386. In an exemplary embodiment, the
valves 190, 195, 200, 315, 386, and 393 include a pressure
differential sensor that may include a spring and spool. In an
exemplary embodiment, each of the valves 190, 195, 200, 315, 386,
and 393 measures and compares two pressures using the spring and
the spool. In an exemplary embodiment, the pilot lines 346 and 381
are in fluid communication with the pressure differential sensor of
the valve 393. In an exemplary embodiment, the pilot lines 327 and
326 are in fluid communication with the pressure differential
sensor of the valve 315. In an exemplary embodiment, the pilot
lines 335 and 345 are in fluid communication with the pressure
differential sensor of the valve 195. In an exemplary embodiment,
the pilot line 380 and the flow path 175 are in fluid communication
with the pressure differential sensor of the valve 200. In an
exemplary embodiment, the pilot lines 387 and 381 are in fluid
communication with the pressure differential sensor of the valve
386. In an exemplary embodiment, the pilot lines 394 and 395 are in
fluid communication with the pressure differential sensor of the
valve 393. In one or more exemplary embodiments, the DPPMP 173, the
SPPMD 392, and the SPPMD 392' form a portion of a wall of the
working string 75 and each of the components (i.e., the valves 190,
195, 200, 315, 386) are of the cartridge type configuration. In one
or more exemplary embodiments, the predetermined pressure range for
each of the first zone 110, the second zone 115, and the third zone
120 is different and dependent upon each zone's formation, depth,
etc.
[0053] In one or more embodiments, the method 400 may be used to
maintain a certain desired excess pressure above the reservoir
pressure in the wellbore annulus 150 to prevent or at least reduce
uncontrolled fluid production into any part of the first zone 110,
the second zone 115, and the third zone 120. In one or more
exemplary embodiments, the method 400 encourages maintaining the
wellbore annulus 150 in a clean state to prevent premature blocking
of a proppant during a frac-pack or gravel pack operation. In one
or more exemplary embodiments, the method 400 prevents or at least
reduces the likelihood of the wellbore 80 collapsing in the case of
an unconsolidated formation. In one or more exemplary embodiments,
the method 400 may maintain the external pressure in the wellbore
annulus 150 for an indefinite amount of time.
[0054] The present disclosure may be altered in a variety of ways.
For example, the reference pressure assembly 310 may be omitted
from the DPPMD 173, the SPPMD 392, and/or the SPPMD 392' and be
replaced by a pressure system that is structurally configured to be
charged to an estimated reservoir pressure at the surface of the
well, such as for example an accumulator that is charged at the
surface of the well. In one or more exemplary embodiments, the
DPPMD 173, the SPPMD 392, and the SPPMD 392' or any combination
thereof may include an isolation sleeve (not shown) that extends
within the completion string annulus 165 and may be moved into a
position to block the openings 185 or 385 or both.
[0055] In one or more exemplary embodiments and illustrated in FIG.
8, another embodiment of the PMD 140 is an Electronic PMD ("EPMD")
450. In one or more exemplary embodiments, the EPMD 450 includes a
tubing 455 that has an exterior surface 455a and an interior
surface 455b. In one or more exemplary embodiments, a fluid path
460 is formed within a wall of the tubing 455 and extends between
an opening 465 in the interior surface 455b and an opening 470
formed in the exterior surface 455a. In an exemplary embodiment,
the fluid path 460 fluidically connects the wellbore annulus 150
with the completion string annulus 165. In one or more exemplary
embodiments, a piston valve 475 is attached to a screw drive 480
that is coupled to a motor 485 and positioned within the fluid path
460 such that activation of the screw drive 480 by the motor 485
moves the piston valve 475 to block the fluid path 460 (as shown in
FIG. 8) or open the fluid path 460 (not shown). Alternatively, a
piston may be attached to a piston/cylinder arrangement that is
coupled to an electrically powered pump. The EPMD 450 may also
include a pressure sensor 490 that is exposed to the completion
string annulus 165, a pressure sensor 492 that is exposed to the
wellbore annulus 150, and a controller 495 that is operably
connected and/or controls the motor 485 and/or the pressure sensors
490 and 492. As illustrated in FIG. 8A, the controller 495 also
includes a computer processor 495a and a computer readable medium
495b operably coupled thereto. Instructions accessible to, and
executable by, the controller 495 are stored on the computer
readable medium 495b. In one or more embodiments, a database 495c
is also stored in the computer readable medium 495b. In one or more
exemplary embodiments, data is stored in the database 495c. In one
or more exemplary embodiments, the data stored in the database 495c
may include: data relating to the predetermined pressure range;
data relating to an ECHO communication methods, etc. However, a
variety of other data may also be stored in the database 495c. In
one or more exemplary embodiments, the EPMD 450 also includes a
power source 500, such as for example batteries. However, any type
of power source 500 is contemplated here. In one or more exemplary
embodiments, the EPMD 450 also includes an isolation sleeve 505
that is slideable along the interior surface 455b of the EPMD 450
from an open position in which the opening 465 is not obstructed by
the isolation sleeve 505 to a closed position in which the opening
465 is obstructed by the isolation sleeve 505. In one or more
exemplary embodiments, the isolation sleeve 505 is located in the
open position when the working string 75 is placed downhole. In one
or more exemplary embodiments, the isolation sleeve 505 is
structurally configured to couple to a downhole tool, such as a
shifting tool, to move the isolation sleeve 505 from the open
position to the closed position and thereby permanently block the
opening 465 and fluid path 460. In one or more exemplary
embodiments, the EPMD 450 is located within the working string
75.
[0056] With reference to FIG. 9 with continuing reference to FIG.
8, in one or more embodiments, a method of operating the EPMD 450
is generally referred to by the reference numeral 510 and may
include positioning the lower completion system 87 including the
EPMD 450 downhole at step 515; isolating a production zone of the
lower completion system 87 at step 520; maintaining the
predetermined pressure range in the production zone of the lower
completion system 87 using the EPMD 450 at step 525; gravel packing
the production zone at step 530; and closing the isolation sleeve
505 of the EPMD 450 at step 535.
[0057] At the step 515, the lower completion system 87, which
includes the EPMD 450, is positioned downhole. In one or more
exemplary embodiments, the isolation sleeve 505 is in the open
position when the lower completion system 87 is positioned
downhole.
[0058] At the step 520, the production zone of the lower completion
system 87 is isolated from the wellbore hydrostatic pressure formed
within the wellbore 80. In one or more exemplary embodiments, the
lower completion system 87 is isolated by the setting of a packer,
such as the packer 90.
[0059] At the step 525, the predetermined pressure range is
maintained in the production zone using the EPMD 450. In one or
more exemplary embodiments, maintaining the predetermined pressure
range in the production zone using the EPMD 450 includes the
controller 495 determining whether the external pressure within the
wellbore annulus 150 as measured by the pressure sensor 492 is less
than the predetermined pressure range. If the external pressure
within the wellbore annulus 150 as measured by the pressure sensor
492 is within the predetermined pressure range or exceeds the
predetermined pressure range, the controller 495 may activate the
motor 485 to move the screw drive 480 and the piston valve 475 to
block the flow path 465 such that fluid from the completion string
annulus 165 does not flow to the wellbore annulus 150. If the
external pressure within the wellbore annulus 150 as measured by
the pressure sensor 492 is below the predetermined pressure range
(and assuming the internal pressure as measured by the pressure
sensor 490 is greater than the external pressure), the controller
495 may activate the motor 485 to move the screw drive 480 and the
piston valve 475 to open the flow path 465 such that the fluid may
flow from the completion string annulus 165 to the wellbore annulus
150. In an exemplary embodiment, the piston valve 475 may also be
partially closed or partially opened to choke the flow of the fluid
from the completion string annulus 165 to the wellbore annulus 150.
In an exemplary embodiment, choking the flow of the fluid from the
completion string annulus 165 to the wellbore annulus 150 allows
the production zone to be pressurized even when the interior
pressure exceeds the predetermined pressure range. In one or more
exemplary embodiments, instructions may be sent from the surface to
the controller 495 using the pressure sensor 490 and a telemetry
system such as, for example, a mud pulse telemetry system. However,
the EPMD 450 may be structurally configured to communicate with any
telemetry system, such as for example an electromagnetic, an
acoustic, a torsion, or a wired drill pipe telemetry system. The
instructions received by the controller 495 may include
instructions to open, close, or choke the fluid path 460. In one or
more exemplary embodiments, the piston valve 475 may be partially
opened when the internal pressure in the completion string annulus
165, as measured by the pressure sensor 490, is greater than the
predetermined pressure range, to choke the flow into the wellbore
annulus 150. In one or more exemplary embodiments, the instructions
received by the pressure sensor 490 may include a new predetermined
pressure range. In an exemplary embodiment, the predetermined
pressure range is defined by a minimum pressure and a maximum
pressure.
[0060] At the step 530, the production zone is gravel packed or
frac-packed. Once the wellbore annulus 150 of the production zone
is gravel packed or frac-packed, the risk of formation collapse is
reduced.
[0061] At the step 535, the isolation sleeve of the EPMD 450 is
closed. In one or more exemplary embodiments, the downhole tool,
such as the shifting tool, is accommodated within the working
string 75 during gravel pack or frac-pack operations. When the
gravel pack or frac-pack operations are completed, the shifting
tool may move uphole. During this movement uphole, the shifting
tool couples to the isolation sleeve 505 and moves the isolation
sleeve 505 from the open position to the closed position. In one or
more exemplary embodiments, moving the isolation sleeve 505 to the
closed position may prevent or at least discourage fluid flow
through the fluid path 460 during production operations.
[0062] In one or more embodiments, the method 510 may be used to
maintain a certain desired excess pressure above the reservoir
pressure in the wellbore annulus 150 to prevent or at least reduce
uncontrolled fluid production into any part of the production zone.
In one or more exemplary embodiments, the method 510 encourages
maintaining the wellbore annulus 150 in a clean state to prevent
premature blocking of the proppant during a frac-pack or gravel
pack operation. In one or more exemplary embodiments, the method
510 prevents or at least reduces the likelihood of the wellbore 80
collapsing in the case of an unconsolidated formation. In one or
more exemplary embodiments, the method 510 may maintain the
external pressure in the wellbore annulus 150 for an indefinite
amount of time. In an exemplary embodiment, the method 510 may be
used to maintain the predetermined pressure range during a variety
of operations, such as for example, during the setting of the
isolation packer, zone pressure testing, frac packing lower zones,
and reversing out lower zones following the frac pack. In an
exemplary embodiment, the method 510 will prevent or at least
reduce the likelihood of cross flow between production zones and
cross flow within one production zone. In one or more exemplary
embodiments, the method 510 may also prevent or at least reduce the
likelihood of over-pressurizing the formation 20.
[0063] The present disclosure may be altered in a variety of ways.
For example, the EPMD 450 may include a Radio-frequency
identification ("RFID") reader or scanner such that when the
shifter tool, which may include a RFID tag, passes near the RFID
reader on the EPMD 450, the controller 495 would move the valve
piston 475 to block the fluid path 460 regardless of the external
pressure as measured by the pressure sensor 492. In one or more
exemplary embodiments, if the shifter tool is tripped back down
again, the RFID tag may signal the EPMD 450 to being maintaining
the predetermined pressure range within the production zone. In one
or more exemplary embodiments, the EPMD 450 may be configured to
include a cartridge rod piston valve. In one or more exemplary
embodiments, the EPMD 450 includes any valve that is controlled by
an electronic module and pressure sensor. Additionally, each
production zone with a multi-zone completion system may be
associated with one (or more) EPMD 450. In another exemplary
embodiment, the EPMD 450 may also include a filter (not shown)
located between the completion string annulus 165 and the piston
valve 475. In an exemplary embodiment, the piston valve 475 acts as
a flow limiter and the EPMD 450 also includes a check valve (not
shown) located between the piston valve 475 and the wellbore
annulus 150. In an exemplary embodiment, the database 495c may
store data relating to a reference pressure that is input at the
surface or updated while the EPMD 450 is downhole using the
telemetry system. That is, the controller 495 may receive
instructions or an updated predetermined pressure range from a
surface system by using pressure pulses detected in the internal
region as measured by the pressure sensor 490. In an exemplary
embodiment, the EPMD 450 may "report" the reservoir pressure to the
surface or other pressure to the surface. In an exemplary
embodiment, the EPMD 450 may also include a timer (not shown) that
is included in the controller 495 or that may communicate with the
controller 495, with the operation of the piston valve 475
dependent upon a time variable measured by the timer. In an
exemplary embodiment, the EPMD 450 may be used to determine the
location of the EPMD 450. For example, if the controller 495
communicates with a surface system that the external pressure or
the internal pressure or both reaches a steady state, then this
steady state could correspond to a desired location of the EPMD 450
within the wellbore 80. In an exemplary embodiment, data or
instructions can be sent from the telemetry system or other system
to the controller 495 to shut down the piston valve 475 during an
unsafe event or other event. That is, the EPMD 450 may be actuated
remotely. In an exemplary embodiment, the EPMD 450 may "report"
localized downhole conditions to the surface, such as for example,
a filter plug.
[0064] In one or more exemplary embodiments and illustrated in
FIGS. 10 and 11, another embodiment of the PMD 140 is an Mechanical
PMD ("MPMD") 555. In one or more exemplary embodiments, the MPMD
555 includes a tubing 557 that is at least partially exposed to the
external region and is at least partially exposed to the internal
region. In one or more exemplary embodiments, a flow path 560
extends from an opening 565 that is in fluid communication with the
external region and to an opening 570 that is in fluid
communication with internal region. The MPMD 555 may include a
valve 575 located along the flow path 560 such that the valve 575
controls the flow of a fluid through the flow path 560. In one or
more exemplary embodiments, the MPMD 555 may also include a flow
regulator 580 and a check valve 585 that form a portion of the flow
path 560. In an exemplary embodiment, the check valve 585 prevents
the fluid from flowing from the external region through the opening
570. In one or more exemplary embodiments, the MPMD 555 may also
include a pilot line 590 that extends between the internal region
and the valve 575. In one or more exemplary embodiments, the MPMD
555 may also include a pilot line 595 that extends between the
external region and the valve 575. In one or more exemplary
embodiments, the valve 575 may be a two-position spool valve that
closes when a pressure differential exceeds a pressure threshold.
In an exemplary embodiment, the valve 575 measures and compares the
internal pressure and the external pressure. In one or more
exemplary embodiments, the pressure differential is the difference
between the internal pressure and external pressure. In one or more
exemplary embodiments, the pressure threshold is a function of a
spring 600 within the valve 575. In one or more exemplary
embodiments, the spring constant of the spring 600 and the initial
pre-compression of the spring 600 is selected to achieve the
pressure threshold for the valve 575. In one or more exemplary
embodiments, the flow regulator 580 is a tube that effects the flow
rate of the fluid passing through the flow regulator 580 based on
the diameter and length of the tube. In one or more exemplary
embodiments, the flow regulator 580 may be any one of a orifice,
nozzle, helix, tortuous path, or other device or structure that
regulates the flow of the fluid flowing through the flow path 560.
In one or more exemplary embodiments, the MPMD 555 may also include
a blocking member, or a lock out device ("LOD") 605 (not shown in
FIG. 11), to permanently close or block the flow path 560.
[0065] In another exemplary embodiment, and as shown in FIG. 12,
the LOD 605 includes a magnetic valve seat 610 that is located
along the flow path 560 such that the flow path 560 is unobstructed
by the magnetic valve seat 610 when the magnetic valve seat 610 is
secured in a first position using shear pins 615 but moves to
obstruct the flow path 560 when moved to a second position. When
moved into the second position, the shear pins 615 are sheared and
the valve seat 610, which may be composed of a magnetic or
ferromagnetic materials, rests against a magnet 620 or a collet
ring, which secures the magnetic valve seat 610 to the magnet 620.
However, a wide variety of components and materials are
contemplated here. For example, the valve seat 610 may be composed
of a magnet and the collet ring may be composed of a ferromagnetic
material or a ferromagnetic materials may be disposed in the tubing
557 such that the valve seat 610 blocks the flow path 560 when the
valve seat 610 is secured against the ferromagnetic materials.
[0066] In one or more exemplary embodiments and as illustrated in
FIG. 13, the LOD 605 is a swellable elastomer 622, such as for
example, a cylinder of rubber swells located along the flow path
560 that swell to close or block the flow path 560. In one or more
exemplary embodiments, an interior surface of the swellable
elastomer 622 defines a portion of the flow path 560 when the
swellable elastomer 622 is in a first configuration, or in the open
position. In one or more exemplary embodiments, the swellable
elastomer 622 swells to a second configuration, or a closed
position, such that the interior surfaces meet to block the flow
path 560. In one or more exemplary embodiments, a rod or other
structure 623 is located proximate the interior surface of the
swellable elastomer 622 to encourage the blocking of the flow path
560 when the swellable elastomer 622 is in the closed position. The
size and materials of the swellable elastomer 622 may be selected
such that the closing of the swellable elastomer 622 occurs after a
predetermined amount of time. In one or more exemplary embodiments,
the swellable elastomer 622 may be located in any area of the valve
575 such that the swelling of the swellable elastomer forces the
valve 575 into a closed position. In one or more exemplary
embodiments, the valve 575 includes the LOD 605. That is, the valve
575 may include shear pins or shear screws that lock the valve 575
in a closed position upon shearing of the shear pins or shear
screws. However, the valve 575 may be secured in a closed position
in a variety of ways, such as for example, a lock ring grabbing a
rod to prevent the rod from returning to open the valve 575.
[0067] In one or more exemplary embodiments, and as illustrated in
FIGS. 14, 15, and 16, another embodiment of the PMD 140 is a MPMD
625 that includes a valve 630 disposed within a tubing 632. In one
or more exemplary embodiments, the valve 630 that may be
three-position spool valve that opens or closes based on a pressure
differential. In one or more exemplary embodiments, the MPMD 625
includes a flow path 635 that extends from an opening 640 within
the tubing 632 and that is exposed to the external pressure to an
opening 645 within the tubing 632 that is exposed to the internal
pressure. In an exemplary embodiment, the valve 630 opens and
closes based on pressure differential between a pressure exerted on
a piston 647 of the valve 630 and either the external pressure or
the internal pressure. In an exemplary embodiment, the valve 630
measures the external pressure. In an exemplary embodiment, a
surface of the piston 647 at least partially defines a gas filled
chamber 650. In an exemplary embodiment, the gas filled chamber 650
is filed with nitrogen gas to a pressure that is a fraction of the
well hydrostatic pressure. In one or more exemplary embodiments, a
spring 655 is disposed within the gas filled chamber 650 and
configured to push against the piston 647. In one or more exemplary
embodiments and when the valve 630 is in the first position as
illustrated in FIG. 16 the gas charge is greater than well
hydrostatics and the spring 655 is in the fully stroked position
and a rod 660 of the valve 630 blocks the flow path 635 near the
opening 645 to close the valve 630. In one or more exemplary
embodiments and when the valve 630 is in the second position, or
the open position, as illustrated in FIG. 15, the gas charge and
spring 655 is partially compressed and is balanced with the well
hydrostatics such that the rod 660 does not block the flow path 635
and fluid may flow from the opening 640 to the opening 645. In one
or more exemplary embodiments, the external pressure exerted on the
piston 647 is sufficient to push the piston 647 and compress the
spring 655, thereby opening the valve 630. In one or more exemplary
embodiments, and as illustrated in FIG. 14, the gas charge and
spring 655 is compressed by the internal pressure through 640 such
that an opening 665 in a seat 670 is blocked by the rod 660 such
that the fluid path 635 is blocked and the valve 630 is closed. In
an exemplary embodiment, the valve 630 is in the position
illustrated in FIG. 16 when located at the surface of the well. In
one or more exemplary embodiments, the valve 630 being closed while
in the first position allows for the lower completion system 87 to
be tested at the surface of the well. In one or more exemplary
embodiments, the spring 655, the gas charge inside of chamber 650,
and/or the size of the rod 660 are selected to create a
predetermined pressure range in which the valve 630 is in the open
position. In one or more exemplary embodiments, the valve 630 may
be any type of valve, such as a shuttle valve. In one or more
exemplary embodiments, the use of the MPMD 625 allows for the valve
630 to open and close based on a pressure differential between at
least in part, an atmospheric pressure or predetermined pressure
and the external pressure or the internal pressure. In an exemplary
embodiment, the MPMD includes the LOD 605.
[0068] The method of operation of the MPMD 555 or the MPMD 625 may
include lowering the lower completion system 87, which includes the
MPMD 555 or the MPMD 625, downhole, isolating a production zone of
the lower completion system 87, maintaining the predetermined
pressure range in the production zone of the lower completion
system 87 using the MPMD 555 or the MPMD 625, gravel packing the
production, and permanently closing the flow path 635 using the LOD
605. At the surface of the well, the pressure exerted on the piston
647 is sufficiently higher than the external pressure to close the
valve 630. As the MPMD 555 or the MPMD 625 is lowered downhole, the
external and internal pressure increases such that the valve 630
opens and fluid flows from the internal region to the external
region. When a packer is set, the internal pressure increase
greatly, thereby closing the valve 630. Once the internal pressure
is reduced, the valve 630 opens to pressurize the external region.
Gravel packing operations may then begin. After a period of time or
once an internal pressure has been reached, the LOD 605 is
activated and the flow path 635 is permanently blocked. In one or
more embodiments, the MPMD 555 or the MPMD 625 may be used to
maintain a certain desired excess pressure above the reservoir
pressure in the wellbore annulus 150 to prevent or at least reduce
uncontrolled fluid production into any part of the production zone.
In one or more exemplary embodiments, the MPMD 555 or the MPMD 625
encourages maintaining the wellbore annulus 150 in a clean state to
prevent premature blocking of the proppant during a frac-pack or
gravel pack operation. In one or more exemplary embodiments, the
MPMD 555 or the MPMD 625 prevents or at least reduces the
likelihood of the wellbore 80 collapsing in the case of an
unconsolidated formation. In an exemplary embodiment, the MPMD 555
or the MPMD 625 may be used to maintain the predetermined pressure
range during a variety of operations, such as for example, during
the setting of the isolation packer, zone pressure testing, frac
packing lower zones, and reversing out lower zones following the
frac pack. In an exemplary embodiment, the MPMD 555 or the MPMD 625
will prevent or at least reduce the likelihood of cross flow
between production zones and cross flow within one production zone.
In one or more exemplary embodiments, the MPMD 555 or the MPMD 625
may also prevent or at least reduce the likelihood of
over-pressurizing the formation 20.
[0069] In one or more exemplary embodiments, the PMD 140 forms a
portion of a wall of the tubing string 87 and each of the
components are of the cartridge type configuration.
[0070] In several exemplary embodiments, the elements and teachings
of the various illustrative exemplary embodiments may be combined
in whole or in part in some or all of the illustrative exemplary
embodiments. In addition, one or more of the elements and teachings
of the various illustrative exemplary embodiments may be omitted,
at least in part, and/or combined, at least in part, with one or
more of the other elements and teachings of the various
illustrative embodiments. For example, and in one or more exemplary
embodiments, the LOD 605 may be present in the DPPMD 173, the SPPMD
392, and the EPMD 450. Additionally, and in one or more exemplary
embodiments, the controller 495 may be present in the DPPMD 173,
the SPPMD 392, the MPMD 555, and the MPMD 625.
[0071] FIG. 17 is a block diagram of an exemplary computer system
1000 adapted for implementing the features and functions of the
disclosed embodiments. In certain embodiments, the computer system
100 may be integrated locally with the PMD 140 while in other
embodiments the computer system 100 may be external from the PMD
140. In one embodiment, the computer system 1000 includes at least
one processor 1002, a non-transitory, computer-readable storage
1004, an optional network communication module 1005, optional I/O
devices 1006, and an optional display 1008, and all interconnected
via a system bus 1009. To the extent a network communications
module 1005 is included, the network communication module 1005 is
operable to communicatively couple the computer system 1000 to
other devices over a network. In one embodiment, the network
communication module 1005 is a network interface card (NIC) and
communicates using the Ethernet protocol. In other embodiments, the
network communication module 1005 may be another type of
communication interface such as a fiber optic interface and may
communicate using a number of different communication protocols. It
is recognized that the computer system 1000 may be connected to one
or more public (e.g. the Internet) and/or private networks (not
shown) via the network communication module 1005. Software
instructions 1010 executable by the processor 1002 for implementing
the PMD 140 in accordance with the embodiments described herein,
may be stored in storage 1004. It will also be recognized that the
software instructions 1010 may be loaded into storage 1004 from a
CD-ROM or other appropriate storage media.
[0072] In several exemplary embodiments, while different steps,
processes, and procedures are described as appearing as distinct
acts, one or more of the steps, one or more of the processes,
and/or one or more of the procedures may also be performed in
different orders, simultaneously and/or sequentially. In several
exemplary embodiments, the steps, processes and/or procedures may
be merged into one or more steps, processes and/or procedures. In
several exemplary embodiments, one or more of the operational steps
in each embodiment may be omitted. Moreover, in some instances,
some features of the present disclosure may be employed without a
corresponding use of the other features. Moreover, one or more of
the above-described embodiments and/or variations may be combined
in whole or in part with any one or more of the other
above-described embodiments and/or variations.
[0073] Thus, a completion assembly has been described. Embodiments
of the assembly may generally include an elongated base pipe having
an external surface at least partially defining an external region
and an internal surface at least partially defining an internal
region; and a pressure maintenance device disposed in the base pipe
and including a first flow path that extends between an opening in
the external surface and an opening in the internal surface; a
first valve that controls the flow of a first fluid from the
internal region to the external region through the first flow path;
a first pressure differential sensor that controls the actuation of
the first valve and is in fluid communication with the external
region; and a pressurized fluid source in fluid communication with
the first pressure differential sensor; wherein a first pressure
differential threshold associated with the first pressure
differential sensor is the difference between a pressure within the
external region and the pressurized fluid source. For any of the
foregoing embodiments, the assembly may include any one of the
following elements, alone or in combination with each other: [0074]
The pressure maintenance device includes a second flow path that
extends between the pressurized fluid source and the external
region; a third valve that controls the flow of a second fluid
through the second flow path and towards the pressurized fluid
source; a third pressure differential sensor that controls the
actuation of the third valve; wherein the third pressure
differential sensor is in fluid communication with the external
region and the first flow path; and wherein a third pressure
differential threshold associated with the third pressure
differential sensor is the difference between a pressure within the
first flow path and the pressure within the external region. [0075]
The pressurized fluid source is an accumulator. [0076] The pressure
maintenance device further including at least one of: a pressure
relief valve that is in fluid communication with the pressurized
fluid source and with the external region; and a rupture disk that
is in fluid communication with the pressurized fluid source and
with the external region. [0077] The pressure maintenance device
further includes a fourth valve that controls the flow of the fluid
through the first flow path, the fourth valve being a flow control
valve; and a fourth pressure differential sensor that controls the
actuation of the fourth valve. [0078] The fourth valve is located
along the first flow path between the opening in the external
surface and the first valve. [0079] The first valve is located
along the first flow path between the fourth valve and the second
valve. [0080] The second valve is located along the first flow path
between the first valve and the opening in the internal
surface.
[0081] Thus, a method for maintaining an isolated portion of an
external region of a completion string within a predetermined
pressure range has been described. Embodiments of the method may
generally include positioning a completion string that has an
internal surface that at least partially defines an internal region
and an external surface that at least partially defines an external
region within a wellbore; pressurizing a pressurized fluid source
located within a pressure maintenance device that is located within
a wall of the completion string to a reference pressure that is
associated with a wellbore hydrostatic pressure within the external
region; isolating a portion of the external region from the
wellbore hydrostatic pressure to form the isolated portion of the
external region; and allowing a first fluid within the internal
region to flow through a first flow path within the pressure
maintenance device to the isolated portion of the external region
when a pressure differential between the external region and the
reference pressure is less than a first pressure differential
threshold that is associated with the predetermined pressure range.
For any of the foregoing embodiments, the method may include any
one of the following elements, alone or in combination with each
other: [0082] Preventing the first fluid within the internal region
from flowing through the first flow path when a pressure
differential between the internal region and the external region
exceeds a second pressure differential threshold. [0083] The
pressurized fluid source includes an accumulator in fluid
communication with the external region. [0084] Pressurizing the
pressurized fluid source to the reference pressure that is
associated with the wellbore hydrostatic pressure within the
external region includes allowing a second fluid to pressurize the
accumulator to the reference pressure when the pressure
differential between a pressure within the first flow path and the
external region is less than a fourth pressure differential
threshold; and preventing the second fluid from pressurizing the
accumulator after the pressure differential between the internal
region and the external region exceeds the fourth pressure
differential threshold. [0085] The pressure maintenance device
includes a relief valve that is in fluid communication with the
pressurized fluid source and with the external region. [0086]
Depressurizing the pressurized fluid source when a first relief
pressure differential threshold associated with the relief valve is
exceeded. [0087] The pressure maintenance device includes a rupture
disk that is in fluid communication with the pressurized fluid
source and with the external region. [0088] Depressurizing the
pressurized fluid source when a second relief pressure differential
threshold associated with the rupture disk is met or exceeded.
[0089] Allowing the first fluid within the internal region to flow
through the first flow path when a pressure differential between
the external region and the reference pressure is less than a first
pressure differential threshold that is associated with the
predetermined pressure range includes opening a first valve that
controls the flow of the first fluid through the first flow path.
[0090] Preventing the first fluid within the internal region from
flowing through the first flow path when a pressure differential
between the internal region and the external region exceeds a
second pressure differential threshold includes closing a second
valve that controls the flow of the first fluid through the first
flow path. [0091] Allowing the first fluid to flow through the
first flow path when a third pressure differential across a third
valve exceeds a third pressure differential threshold associated
with the third valve. [0092] Isolating a portion of the external
region to form the isolated portion of the external region includes
setting a packer that is disposed on the completion string.
[0093] Thus, a method of providing pressure maintenance is
described. Embodiments of the method may generally include
positioning a completion string within a wellbore, the completion
string having an internal surface that at least partially defines
an internal region and an external surface that at least partially
defines an external region; isolating a portion of the external
region from a wellbore hydrostatic pressure; fluidically connecting
the internal region to the isolated portion of the external region
via a first flow path; providing a first valve that controls the
flow of a first fluid through the first flow path, the first valve
including a first pressure differential sensor; opening the first
valve when the first pressure differential sensor measures a
pressure differential between an external pressure within the
isolated portion of the external region and a reference pressure
that is less than a first pressure threshold; and closing the first
valve when the pressure differential between the external pressure
and the reference pressure is greater than or equal to the first
pressure threshold. For any of the foregoing embodiments, the
method may include any one of the following, alone or in
combination with each other: [0094] Providing a second valve that
controls the flow of the first fluid through the first flow path,
the second valve including a second pressure differential sensor.
[0095] Opening the second valve when the second pressure
differential sensor measures a pressure differential between an
internal pressure associated with the internal region and the
external pressure that is less than a second pressure threshold.
[0096] Closing the second valve when the pressure differential
between the internal pressure and the external pressure within the
isolated portion of the external region is greater than or equal to
the second pressure threshold. [0097] Providing a flow control
valve that controls the flow of the first fluid through the first
flow path. [0098] Pressurizing an accumulator that is located
within the completion string and that is in fluid communication
with the external region to the external pressure. [0099]
Pressurizing the accumulator includes flowing a second fluid from
the external region in a direction towards the accumulator. [0100]
Closing a fifth valve that controls the flow of the second fluid
when a fifth pressure differential sensor measures a pressure
differential between the first flow path and the external pressure
that is greater than a fifth pressure threshold associated with the
fifth pressure differential sensor. [0101] The first pressure
differential sensor includes a spring. [0102] The reference
pressure is the wellbore hydrostatic pressure.
[0103] The foregoing description and figures are not drawn to
scale, but rather are illustrated to describe various embodiments
of the present disclosure in simplistic form. Although various
embodiments and methods have been shown and described, the
disclosure is not limited to such embodiments and methods and will
be understood to include all modifications and variations as would
be apparent to one skilled in the art. Therefore, it should be
understood that the disclosure is not intended to be limited to the
particular forms disclosed. Accordingly, the intention is to cover
all modifications, equivalents and alternatives falling within the
spirit and scope of the disclosure as defined by the appended
claims.
* * * * *